ice dams and proper roof ventilation


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Old 01-29-04, 02:55 PM
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ice dams and proper roof ventilation

Hello , I'm having a problem with ice dams, I have water coming into the house from the top of my windows because of them. The roof was just done 5 years ago(before I owned the house) and its the third layer of shingles. A peak cap was installed but I feel it was not installed properly,instead of sawing off the plywood at the top they drilled a series of 1 inch holes ,Im not even sure how many and if the holes are clear of debris. I have no eve vents, just two windows wich I have closed before the winter( Probably a mistake, I just opened them back up). Should I have a roofer properly install this peak vent cap? The attic floor is properly insulated,It is a ranch style house. Any thoughts? Thanks.

FBAR
 
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Old 01-29-04, 04:10 PM
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Whoever did the roof sounds like a moron to me.

1. 3 layers is shingles is wrong, wrong, wrong. I'm sure someone will flame me for this but it goes against common sense, good practice (and in some cases local code).

2. Why the heck would someone take the time to drill 1" holes instead of putting on a carbide blade and ripping the 1" wide gap.

3. Leave the eve vents blocked, they will tend to work AGAINST the effectiveness of the ridge vents, BUT YOU NEED SOFFIT VENTS TO MAKE THE RIDGE VENT WORK.

Since I don't live in an area where iced dams are a problems I'm sure someone who does, like Jack The Contractor, will come in with anything else you need for the cold area.

Frank
 
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Old 01-30-04, 06:54 AM
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3 layers is not preferred but depends on the code. We have done third layers in the past but only on request and we always severly limit our warranties. It's pretty much our preference to always tear off since you can identify any and every problem the roof has had, and then correct them.

Yes the roofer should have saw cut the ridge vent from end to end (1' termination before the edges of the roof or chimneys). The only problem with ridge vents is they don't work as well without intake (soffit/eave vents). Many manufacturers of ridge vent specify equal or greater intake ventilation. I can't see the 1" holes going faster than a circular saw cut. The holes must have taken twice as long to drill. More infor on ridge vents can be found at www.rollvent.com or www.airvent.com These are two major ventilation manufacturers.

Frank, aren't soffit and eave vents the same? I've always referred to them as the same thing, since the eaves are the overhangs are the soffits. When you say eve vents do you mean gable vents?

As it is, your shingle warranty is probably void due to improper ventilation. You need that ridge vent to be installed properly, which means removing the existing vent.

Fbar other things you need to look out for are bathroom or attic vents that terminate in the attic. THis will cause condensation which may appear like ice damning from the inside. It's too late to install Ice shield, since it needs to be installed dirctly onto the substrate (roof deck). The roof is 5 years old? It may be under warranty. Consider asking the previous roofer to fix the ridge vent for free, or paying a real professional to fix it at his expense.
 
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Old 01-30-04, 07:58 AM
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Roof

I know its hardto say yes to the cost. But down the line Id say you will save $$$$.
Id get some one in to reroof the whole thing and do it right from takeing the old roof off, vents in the over hang. For me I like button vents by the ridge .With snow the ridge vent can get blocked. Ice shield on the over hang. ED
 
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Old 01-30-04, 04:03 PM
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Not only is that ridge vent installation wrong, you need proper venting at the soffits. Plus something nobody mentioned, you also need proper attic insulation. You can have the best vents top and bottom and still have ice damn problems due to improper or lack of insulation. Without looking it up, i think an attic is supposed to have R30. Blown insulation to the tops of the joists is not sufficient for cold climates and that is all a lot of houses have.
 
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Old 01-30-04, 05:03 PM
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Hello again and thanks for the feedback,I will look into that possible warranty, I have a soffit along the entire front of the house but none in the back, if I had soffit vents cut in at 2 foot intervals - would that be enough intake? I do have the two windows at each gable end I would keep open. The attic floor is insulated with r-19,its the best I can do with 2x6 rafters and a floor I want to use for storage and such. no insulation on the roof rafters of course. Interesting point about the condensation theory, no vents terminate in the attic but I do have my humidyfier set at 40 % , pretty high for these 10 - 15 degree New York days.I did hear water dripping inside the walls though , not sure if condensation would cause that , I'll lower the stat to 30% though.( or lower?) Thanks again ,FBAR.
 
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Old 01-31-04, 05:05 AM
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Just grabbed my reference book..

Recommended insulation values..

Climate: Northern Temperate Southern
attic: R38 R30 R26
walls: R19 R19 R19
floors: R22 R13 R11
 
 

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